Sodapop: Sweetie Pie; Ever since the day Soda met you, he always called you sweetie pie, now that you're together it means the world for him to call you that.
Steve: Sweetcakes; Everyone knows Steve loves cakes! And he loves you! So it only makes since that he would call you his sweetcakes :)
Dally: Baby; Dally called you baby because he wanted everyone to know that you're his baby girl.
Two-Bit: Minnie; Two-Bit loved Mickey Mouse and he loved Mickey and Minnie's relationship, he wanted yours just like it! ♡
Darry: Angel; He called you angel because he always worked on roofs and when he looked at the sky while working on the roof, he'd think on angles, and you, his angel.
Johnny; Goldie; Ever since he heard Ponyboy tell him that poem, he couldn't stop thinking of you. He wanted you to stay gold and be his golden girl.
Ponyboy: Honey; He wanted you to be the honey to his bee. (I'm sorry for the cheesy pun lol)